1. Scope of the Invention
The present invention relates to three-dimensional (3D) imaging, and more specifically, 3D imaging of less intense structures near dominant structures.
2. Discussion of Prior Art
In many different types of imaging, a large, or intense source will dominate and hide weaker, less intense, or smaller sources. This may appear in different types of imaging. One specific type is medical imaging, and mores specifically cardiac imaging.
Coronary artery disease is the leading cause of death in the United States and a major contribution to health care costs. Despite recent advances in magnetic resonance (MR) cardiac imaging, and x-ray catheterization, coronary angiography is the definitive examination for coronary artery disease. Coronary arteries are examined on medical images from different viewpoints using contrast material injected with a catheter into either the right or left coronary while examined under fluoroscopic imaging. The coronary arteries are small, less intense sources, as compared with the blood pools of the atria, ventricles and aorta, which dominate coronary images. If coronary arteries could be more clearly imaged, coronary artery disease could be diagnosed by viewing the coronary artery tree. And more specifically if the images could be obtained with MR imaging, patients may not require painful catheterization.
Manual methods for removing the blood pool from an acquired medical image data set before display are described in "Coronary Arteries: Three-dimensional MR Imaging with Respective Respiratory Gating" by D Li, S Kaushikkar, E M Haacke et al, Radiology 201, 857-863 (1996). This requires tedious manual user interaction to trace the outline of the coronary arteries.
Other strategies for segmenting the coronary arteries may find vessels by connectivity or tracking the lumen. However, discontinuities in the vessels and noise connecting the vessels to the blood pool may defeat automatic vessel finding techniques.
Currently, there is s need for a system which automatically produces images of smaller, less intense structures in a region near a larger, dominant structures.